Propose of high performance resistive type H_2S and CO_2 gas sensing response of reduced graphene oxide/titanium oxide (rGO/TiO_2) hybrid sensors

摘要

Few studies have investigated the electrical and gas sensing properties of reduced graphene oxide/titanium dioxide (rGO/ TiO_2) composite thin films by spray pyrolysis technique. In this work, we report the synthesis and systematic investigation of structural, morphological and gas sensing properties of rGO-loaded TiO_2 nanocomposite thin films. The XRD and AFM results suggest that both pure and rGO/TiO_2 nanocomposite showed crystalline with tetragonal anatase phase and individual spherical shaped nanoparticles with average diameter of around 20-30 nm was observed. rGO/TiO_2, nanocomposite showed high surface area (112 m~2/g) and larger pores (11.2 nm) than bare TiO_2 (89 m~2/g; 32.3 nm). This huge surface area can beneficial for enhancing the gas sensing performance. Resistive type gas sensor set up was constructed and studied the sensing responses towards H_2S and CO_2 gases. The results suggest that the rGO/TiO_2 nanocomposite sensor showed high sensitivity (92%), stability (only loss 3.5%), fast response (30 s) and recovery time (25 s) towards CO_2 gas. The improved gas sensing mechanism of the proposed sensor was discussed in detail.